Abstract: The apparent complexity of the laser‐plasma coupling in laser fusion target irradiation has stimulated the need for carefully controlled experimental studies of the laser‐plasma interaction at the critical surface. A helium Z pinch has been constructed which produces a high density plasma, independent of the laser, enabling the separation of the laser‐plasma interaction physics from the plasma formation mechanism. Its peak electron density (4×1019 cm−3), critical density scale length (70–200 μ), and temperature (∼25 eV) make it suitable for simulating and studying laser‐pellet interaction mechanisms at CO2 laser wavelengths. Detailed numerical modelling of these experiments was employed as a check against our diagnostics, as well as providing physical insight in those ranges of experimental parameters where measurements were not made.